With the latest update there are new images for the egg chest and vaults. Has anyone identified the link between the outside image and the contents? I'm guessing the one with stones on top would give rock dragon eggs while the one with vines would give grass dragon eggs, but has anyone found a correlation for the rest?

So far I've seen a red chest with a patch, maybe Crimson Dragon?
Blue chest with a patch?
And Black with a patch, maybe Cosmos or Gargoyle Dragon?